[YouTube] Latest Video: Prevent unnecessary API requests for invalid channels

Valid channel IDs/users do not contain any spaces, so they're safe to ignore (for now)

Author: Decicus

app/Http/Controllers/YouTubeController.php

@@ -41,6 +41,22 @@ public function latestVideo(Request $request)
             $skip = 0;
         }
 
+        /**
+         * Channel IDs and old "user" URLs do not have spaces in them.
+         *
+         * Some users have specified their display names (example: "My Channel Name")
+         * as their channel ID, which will just return an error from the YouTube API.
+         *
+         * To prevent unnecessary API requests, we're returning an error early as
+         * this would be an invalid ID/user value anyways.
+         */
+        if (strpos($id, ' ') !== false) {
+            return Helper::text(__('youtube.invalid_channel_value', [
+                'type' => $type,
+                'id' => $id,
+            ]));
+        }
+
         try {
             switch ($type) {
                 case 'user':

resources/lang/en/youtube.php

@@ -0,0 +1,13 @@
+<?php
+
+/**
+ * English translation strings for YouTube-related endpoints.
+ */
+
+return [
+    /**
+     * For /youtube/latest_video when someone specifies an
+     * invalid channel ID (/channel/ URLs) or user (/user/ URLs).
+     */
+    'invalid_channel_value' => 'Invalid YouTube channel (:type) specified: :id',
+];